Project overview

Ronald AF is inspired by the chunky 1975 Roland AF-60 Bee Gee, renowned for being the standalone version of the “jet mode” found in the legendary AP-7 Jet Phaser. A pedal primarily described as a fuzz box, with a characteristic distortion and sustain that has garnered more than a few clone attempts on the market. Go Sabbath on this build, and you will understand what it is actually all about.

Introduction

Featuring a blend of transistor gain, op-amp gain, and diode-based hard clipping to define its unique character. The tone control follows the classic Big Muff “balance” style, centered around 1.3Khz, with a subtle mid-boost in the middle position.

One key modification Ronald AF has over the original is the inclusion of the gain control, allowing for adjustable distortion levels. In the original, the op-amp gain was fixed at 220, but it’s now possible to reduce it to as low as 2, pushing it into overdrive territory rather than full-on fuzz. When the gain control is at its maximum, the circuit gives you an exact replica of the vintage AF-60.

Controls

Potentiometers

• DISTORTION
• LEVEL
• TONE

For any technical questions regarding this build don’t forget to check out our Facebook Group and our forum at Free Stomp Boxes.

Building Docs coming soon, stay tuned! 

Ronald AF – Drilling template